Study finds larger-than-expected gap in medication nonadherence

By Antoinette Alexander

WOONSOCKET, R.I. A recent study by CVS Caremark and Horizon Blue Cross Blue Shield looked at e-prescribing data and found that not only are a significant number of patients with chronic illnesses not filling their prescriptions, but the issue of nonadherence also is larger than previously thought.

"Most previous studies on primary nonadherence have depended upon patient self-reporting or focused on hospital populations that could be tracked more closely," stated Joshua Liberman, VP strategic research for CVS Caremark and the study's primary author. "With the increasing use of e-prescribing we can now get a more accurate picture of how many members fail to fill that first prescription and insights into factors associated with that failure."

The review by CVS Caremark looked at e-prescriptions by 507 doctors in the Horizon Blue Cross Blue Shield of New Jersey network between January 2006 and Oct. 31, 2006. The study reviewed only e-prescriptions written for the two chronic illnesses, which gives a clearer indication of those not filling their initial prescription because electronic orders reach drug stores immediately and claims data shows which prescriptions are picked up -- or not.

The study, published this week in the American Journal of Pharmacy Benefits, found that more than 20% of patients who were prescribed asthma controllers and more than 34% of patients who were prescribed medications for high cholesterol did not fill their initial prescriptions.

Furthermore, the study indicates that the issue of non-adherence is larger than previously thought and highlights the need for additional education efforts and intervention programs to improve the likelihood of patients adhering to the protocols prescribed by their doctor.

Nonadherence to essential medications is a frequent cause of preventable hospitalizations and patient illness, with costs to the U.S. healthcare system estimated at about $300 billion annually.